Acute liver failure

TTP protects against acute liver failure by regulating CCL2 and CCL5 through m6A RNA methylation

Tristetraprolin (TTP), an important immunosuppressive protein regulating mRNA decay through recognition of the AU-rich elements (AREs) within the 3′-UTRs of mRNAs, participates in the pathogenesis of liver diseases. However, whether TTP regulates mRNA stability through other mechanisms remains poorly understood. Here, we report that TTP was upregulated in acute liver failure (ALF), resulting in decreased mRNA stabilities of CCL2 and CCL5 through promotion of N⁶-methyladenosine (m⁶A) mRNA methylation. Overexpression of TTP could markedly ameliorate hepatic injury in vivo. TTP regulated the mRNA stabilization of CCL2 and CCL5. Interestingly, increased m⁶A methylation in CCL2 and CCL5 mRNAs promoted TTP-mediated RNA destabilization. Moreover, induction of TTP upregulated expression levels of WT1 associated protein, methyltransferase like 14, and YT521-B homology N⁶-methyladenosine RNA binding protein 2, which encode enzymes regulating m⁶A methylation, resulting in a global increase of m⁶A methylation and amelioration of liver injury due to enhanced degradation of CCL2 and CCL5. These findings suggest a potentially novel mechanism by which TTP modulates mRNA stabilities of CCL2 and CCL5 through m⁶A RNA methylation, which is involved in the pathogenesis of ALF.

Kinetics of Bilirubin and Ammonia Elimination during Hemadsorption Therapy in Secondary Sclerosing Cholangitis Following ECMO Therapy and Severe COVID-19

In critically ill patients, liver dysfunction often results in coagulopathy and encephalopathy and is associated with high mortality. Extracorporeal clearance of hepatotoxic metabolites, including bilirubin and ammonia, aims to attenuate further hepatocyte damage and liver injury, resulting in decreased mortality. The efficacy of hemadsorption combined with conventional hemodialysis to eliminate bilirubin and ammonia to support the liver's excretory function in acute liver injury has been described previously. However, the optimal use of liver support systems in chronic liver dysfunction due to secondary sclerosing cholangitis in critically ill patients (SSC-CIP) has not been defined yet. We herein describe the kinetics of successful bilirubin and ammonia elimination by hemadsorption in a patient with SSC-CIP after extracorporeal membrane oxygenation (ECMO) therapy for severe acute respiratory distress syndrome (ARDS) in a patient with coronavirus disease 2019 (COVID-19). During the course of the disease, the patient developed laboratory signs of liver injury during ECMO therapy before clinically detectable jaundice or elevated bilirubin levels. A diagnosis of SSC-CIP was confirmed by endoscopic retrograde cholangiopancreatography (ERCP) based on intraductal filling defects in the intrahepatic bile ducts due to biliary casts. The patient showed stable elevations of bilirubin and ammonia levels thereafter, but presented with progressive nausea, vomiting, weakness, and exhaustion. Based on these laboratory findings, hemadsorption was combined with hemodialysis treatment and successfully eliminated bilirubin and ammonia. Moreover, direct comparison revealed that ammonia is more efficiently eliminated by hemadsorption than bilirubin levels. Clinical symptoms of nausea, vomiting, weakness, and exhaustion improved. In summary, bilirubin and ammonia were successfully eliminated by hemadsorption combined with hemodialysis treatment in SSC-CIP following ECMO therapy and severe COVID-19. This observation is particularly relevant since it has been reported that a considerable subset of critically ill patients with COVID-19 suffer from liver dysfunction associated with high mortality.

Unexpected spotlight on two unusual substances

Acute liver failure (ALF) is a rare and unexpected condition, which is commonly related to drug ingestion and viral infections. Here, two ALF fatalities are presented, which showed a rapid progression between the onset of symptoms and death. Both cases gained attention as unusual substances were suspected to be the reason for the fatal ALF, namely the prescription-free natural remedy Iberogast® (Bayer Vital GmbH, Leverkusen, Germany) and freely available energy drinks. Autopsy findings revealed that the fatal ALFs were unrelated to the ingestion of these two substances.

Mesenchymal stromal cells mitigate liver damage after extended resection in the pig by modulating thrombospondin-1/TGF-β

Post-surgery liver failure is a serious complication for patients after extended partial hepatectomies (ePHx). Previously, we demonstrated in the pig model that transplantation of mesenchymal stromal cells (MSC) improved circulatory maintenance and supported multi-organ functions after 70% liver resection. Mechanisms behind the beneficial MSC effects remained unknown. Here we performed 70% liver resection in pigs with and without MSC treatment, and animals were monitored for 24 h post surgery. Gene expression profiles were determined in the lung and liver. Bioinformatics analysis predicted organ-independent MSC targets, importantly a role for thrombospondin-1 linked to transforming growth factor-β (TGF-β) and downstream signaling towards providing epithelial plasticity and epithelial-mesenchymal transition (EMT). This prediction was supported histologically and mechanistically, the latter with primary hepatocyte cell cultures. MSC attenuated the surgery-induced increase of tissue damage, of thrombospondin-1 and TGF-β, as well as of epithelial plasticity in both the liver and lung. This suggests that MSC ameliorated surgery-induced hepatocellular stress and EMT, thus supporting epithelial integrity and facilitating regeneration. MSC-derived soluble factor(s) did not directly interfere with intracellular TGF-β signaling, but inhibited thrombospondin-1 secretion from thrombocytes and non-parenchymal liver cells, therewith obviously reducing the availability of active TGF-β.

Recommendations for the use of the acetaminophen hepatotoxicity model for mechanistic studies and how to avoid common pitfalls

Acetaminophen (APAP) is a widely used analgesic and antipyretic drug, which is safe at therapeutic doses but can cause severe liver injury and even liver failure after overdoses. The mouse model of APAP hepatotoxicity recapitulates closely the human pathophysiology. As a result, this clinically relevant model is frequently used to study mechanisms of drug-induced liver injury and even more so to test potential therapeutic interventions. However, the complexity of the model requires a thorough understanding of the pathophysiology to obtain valid results and mechanistic information that is translatable to the clinic. However, many studies using this model are flawed, which jeopardizes the scientific and clinical relevance. The purpose of this review is to provide a framework of the model where mechanistically sound and clinically relevant data can be obtained. The discussion provides insight into the injury mechanisms and how to study it including the critical roles of drug metabolism, mitochondrial dysfunction, necrotic cell death, autophagy and the sterile inflammatory response. In addition, the most frequently made mistakes when using this model are discussed. Thus, considering these recommendations when studying APAP hepatotoxicity will facilitate the discovery of more clinically relevant interventions.

Effect of dihydromyricetin on hepatic encephalopathy associated with acute hepatic failure in mice

CONTEXT

Hepatic encephalopathy (HE) is a complex neuropsychiatric disease caused by liver failure. Dihydromyricetin (DMY) is a traditional medicine used to treat liver injury.

OBJECTIVE

To investigate the effects of dihydromyricetin (DMY) on hepatic encephalopathy associated with acute hepatic failure mice models established by thioacetamide (TAA) exposure.

MATERIALS AND METHODS

Female BALB/c mouse were randomly divided into control, DMY, TAA, and TAA + DMY groups (n = 8). The first two groups were intraperitoneally injected with saline or 5 mg/kg DMY, respectively. The last two groups were injected with 600 mg/kg TAA to establish HE models, and then the mice in the last group were treated with 5 mg/kg DMY. Neurological and cognition functions were evaluated 24 and 48 h after injection. Mice were sacrificed after which livers and brains were obtained for immunoblot and histopathological analysis, while blood was collected for the analysis of liver enzymes.

RESULTS

In the TAA + DMY group, ALT and AST decreased to 145.31 ± 12.88 U/L and 309.51 ± 25.92 U/L, respectively, whereas ammonia and TBIL decreased to 415.67 ± 41.91 μmol/L and 3.31 ± 0.35 μmol/L, respectively. Moreover, MDA decreased to 10.74 ± 3.97 nmol/g, while SOD and GST increased to 398.69 ± 231.30 U/g and 41.37 ± 21.84 U/g, respectively. The neurological score decreased to 2.87 ± 0.63, and the number of GFAP-positive cells decreased to 41.10 ± 1.66. Furthermore, the protein levels of TNF-α, IL-6, and GABA_A in the cortex decreased.

CONCLUSIONS

We speculate that DMY can serve as a novel treatment for HE.

Hypophosphatemia in acute liver failure of a broad range of etiologies is associated with phosphaturia without kidney damage or phosphatonin elevation

Hypophosphatemia is a common and dangerous complication of acute liver failure (ALF) of various etiologies. While various mechanisms for ALF-associated hypophosphatemia have been proposed including high phosphate uptake into regenerating hepatocytes, acetaminophen (APAP)-associated hypophosphatemia was linked to renal phosphate wasting, and APAP-induced renal tubular injury was proposed as underlying mechanism. We studied 30 normophosphatemic and 46 hypophosphatemic (serum phosphate < 2.5 mg/dL) patients from the Acute Liver Failure Study Group registry with APAP- or non-APAP-induced ALF. Since kidney injury affects phosphate excretion, patients with elevated serum creatinine (>1.2 mg/dL) were excluded. Maximal amount of renal tubular phosphate reabsorption per filtered volume (TmP/GFR) was calculated from simultaneous serum and urine phosphate and creatinine levels to assess renal phosphate handling. Instead of enhanced renal phosphate reabsorption as would be expected during hypophosphatemia of non-renal causes, serum phosphate was positively correlated with TmP/GFR in both APAP- and non-APAP-induced ALF patients (R2 = 0.66 and 0.46, respectively; both P < 0.0001), indicating renal phosphate wasting. Surprisingly, there was no evidence of kidney damage based on urinary markers including neutrophil gelatinase-associated lipocalin and cystatin C even in the APAP group. Additionally, there was no evidence that the known serum phosphatonins parathyroid hormone, fibroblast growth factor 23, and α-Klotho contribute to the observed hypophosphatemia. We conclude that the observed hypophosphatemia with renal phosphate wasting in both APAP- and non-APAP-mediated ALF is likely the result of renal tubular phosphate leak from yet-to-be identified factor(s) with no evidence for proximal tubular damage or contribution of known phosphatonins.

A Comparative Study of the Hepatoprotective Effect of Centella asiatica Extract (CA-HE50) on Lipopolysaccharide/d-galactosamine-Induced Acute Liver Injury in C57BL/6 Mice

Acute liver failure (ALF) refers to the sudden loss of liver function and is accompanied by several complications. In a previous study, we revealed the protective effect of Centella asiatica 50% ethanol extract (CA-HE50) on acetaminophen-induced liver injury. In the present study, we investigate the hepatoprotective effect of CA-HE50 in a lipopolysaccharide/galactosamine (LPS-D-Gal)-induced ALF animal model and compare it to existing therapeutic silymarin, Lentinus edodes mycelia (LEM) extracts, ursodeoxycholic acid (UDCA) and dimethyl diphenyl bicarboxylate (DDB). Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were decreased in the CA-HE50, silymarin, LEM, UDCA and DDB groups compared to the vehicle control group. In particular, AST and ALT levels of the 200 mg/kg CA-HE50 group were significantly decreased compared to positive control groups. Lactate dehydrogenase (LDH) levels were significantly decreased in the CA-HE50, silymarin, LEM, UDCA and DDB groups compared to the vehicle control group and LDH levels of the 200 mg/kg CA-HE50 group were similar to those of the positive control groups. Superoxide dismutase (SOD) activity was significantly increased in the 100 mg/kg CA-HE50, LEM and UDCA groups compared to the vehicle control group and, in particular, the 100 mg/kg CA-HE50 group increased significantly compared to positive control groups. In addition, the histopathological lesion score was significantly decreased in the CA-HE50 and positive control groups compared with the vehicle control group and the histopathological lesion score of the 200 mg/kg CA-HE50 group was similar to that of the positive control groups. These results show that CA-HE50 has antioxidant and hepatoprotective effects at a level similar to that of silymarin, LEM, UDCA and DDB, which are known to have hepatoprotective effects; further, CA-HE50 has potential as a prophylactic and therapeutic agent in ALF.

The Immunological Mechanisms and Immune-Based Biomarkers of Drug-Induced Liver Injury

Drug-induced liver injury (DILI) has become one of the major challenges of drug safety all over the word. So far, about 1,100 commonly used drugs including the medications used regularly, herbal and/or dietary supplements, have been reported to induce liver injury. Moreover, DILI is the main cause of the interruption of new drugs development and drugs withdrawn from the pharmaceutical market. Acute DILI may evolve into chronic DILI or even worse, commonly lead to life-threatening acute liver failure in Western countries. It is generally considered to have a close relationship to genetic factors, environmental risk factors, and host immunity, through the drug itself or its metabolites, leading to a series of cellular events, such as haptenization and immune response activation. Despite many researches on DILI, the specific biomarkers about it are not applicable to clinical diagnosis, which still relies on the exclusion of other causes of liver disease in clinical practice as before. Additionally, circumstantial evidence has suggested that DILI is mediated by the immune system. Here, we review the underlying mechanisms of the immune response to DILI and provide guidance for the future development of biomarkers for the early detection, prediction, and diagnosis of DILI.

A Retrospective Analysis of COVID-19-infected Patients with Acute Hepatitis who Develop Acute Liver Failure in a Safety Net Hospital

OBJECTIVE

In early 2019, a new coronavirus called SARS-CoV-2 emerged and changed the course of civilization. Our study aims to analyze the association between acute liver failure (ALF) and mortality in patients infected with COVID-19. A retrospective analysis of 864 COVID-19-infected patients admitted to Nassau University Medical Center in New York was performed.

DESIGN

ALF is identified by acute liver injury (elevations in liver enzymes), hepatic encephalopathy and an international normalised ratio greater than or equal to 1.5. These parameters were analysed via daily blood work and clinical assessment. Multivariate logistic regression model predicting mortality and controlling for confounders such as age, coronary artery disease, intubation, hypertension, diabetes mellitus and acute kidney injury were used to determine the association of ALF with mortality.

RESULTS

A total of 624 patients, out of the initial 864, met the inclusion criteria-having acute hepatitis and COVID-19 infection. Of those 624, 43 (6.9%) patients developed ALF during the course of their hospitalisation and their mortality rate was 74.4%. The majority of patients with ALF were male (60.6%). The logistic model predicting death and controlling for confounders shows COVID-19 patients with ALF had a nearly four-fold higher odds of death in comparison to those without ALF (p=0.0063).

CONCLUSIONS

Findings from this study suggest that there is a significant association between mortality and the presence of ALF in patients infected with COVID-19. Further investigation into patients with COVID-19 and ALF can lead to enhanced treatment regimens and risk stratification tools, which can ultimately improve mortality rates during these arduous times.

Human hepatocyte-derived extracellular vesicles attenuate the carbon tetrachloride-induced acute liver injury in mice

Acute liver injury (ALI) induced by chemicals or viruses can progress rapidly to acute liver failure (ALF), often resulting in death of patients without liver transplantation. Since liver transplantation is limited due to a paucity of donors, expensive surgical costs, and severe immune rejection, novel therapies are required to treat liver injury. Extracellular vesicles (EVs) are used for cellular communication, carrying RNAs, proteins, and lipids and delivering them intercellularly after being endocytosed by target cells. Recently, it was reported that EVs secreted from human hepatocytes have an ability to modulate the immune responses; however, these roles of EVs secreted from human hepatocytes were studied only with in vitro experiments. In the present study, we evidenced that EVs secreted from human hepatocytes attenuated the CCL₄-induced ALI by inhibiting the recruitment of monocytes through downregulation of chemokine receptor in the bone marrow and recruitment of neutrophils through the reduction of C-X-C motif chemokine ligand 1 (CXCL1) and CXCL2 expression levels in the liver.

Combination of Trans-Resveratrol and ε-Viniferin Induces a Hepatoprotective Effect in Rats with Severe Acute Liver Failure via Reduction of Oxidative Stress and MMP-9 Expression

Stilbenes are a major grapevine class of phenolic compounds, known for their biological activities, including anti-inflammatory and antioxidant, but never studied in combination. We aimed to evaluate the effect of trans-resveratrol + ε-viniferin as an antioxidant mixture and its role in inflammatory development an in vivo model of severe acute liver failure induced with TAA. Trans-resveratrol + trans-ε-viniferin (5 mg/kg each) was administered to Wistar rats. Resveratrol + ε-viniferin significantly decreased TBARS and SOD activity and restored CAT and GST activities in the treated group. This stilbene combination reduced the expression of TNFα, iNOS, and COX-2, and inhibited MMP-9. The combination of resveratrol + ε-viniferin had a hepatoprotective effect, reducing DNA damage, exhibiting a protective role on the antioxidant pathway by altering SOD, CAT, and GST activities; by downregulating TNFα, COX-2, and iNOS; and upregulating IL-10. Our results suggested that adding viniferin to resveratrol may be more effective in hepatoprotection than resveratrol alone, opening a new perspective on using this stilbene combination in functional diets.

Autophagy plays a double-edged sword role in liver diseases

As a highly evolutionarily conserved process, autophagy can be found in all types of eukaryotic cells. Such a constitutive process maintains cellular homeostasis in a wide variety of cell types through the encapsulation of damaged proteins or organelles into double-membrane vesicles. Autophagy not only simply eliminates materials but also serves as a dynamic recycling system that produces new building blocks and energy for cellular renovation and homeostasis. Previous studies have primarily recognized the role of autophagy in the degradation of dysfunctional proteins and unwanted organelles. However, there are findings of autophagy in physiological and pathological processes. In hepatocytes, autophagy is not only essential for homeostatic functions but also implicated in some diseases, such as viral hepatitis, alcoholic hepatitis, and hepatic failure. In the present review, we summarized the molecular mechanisms of autophagy and its role in several liver diseases and put forward several new strategies for the treatment of liver disease.

HBx facilitates ferroptosis in acute liver failure via EZH2 mediated SLC7A11 suppression

Background

Acute liver failure (ALF) is a syndrome of severe hepatocyte injury with high rate of mortality. Hepatitis B virus (HBV) infection is the major cause of ALF worldwide, however, the underlying mechanism by which HBV infection leads to ALF has not been fully disclosed.

Methods

D-GalN-induced hepatocyte injury model and LPS/D-GalN-induced ALF mice model were used to investigate the effects of HBV X protein (HBx) in vitro and in vivo, respectively. Cell viability and the levels of Glutathione (GSH), malondialdehyde (MDA) and iron were measured using commercial kits. The expression of ferroptosis-related molecules were detected by qRT-PCR and western blotting. Epigenetic modification and protein interaction were detected by chromatin immunoprecipitation (ChIP) assay and co-immunoprecipitation (co-IP), respectively. Mouse liver function was assessed by measuring aspartate aminotransferase (AST) and alanine aminotransferase (ALT). The histological changes in liver tissues were monitored by hematoxylin and eosin (H&E) staining, and SLC7A11 immunoreactivity was assessed by immunohistochemistry (IHC) analysis.

Results

D-GalN triggered ferroptosis in primary hepatocytes. HBx potentiated D-GalN-induced hepatotoxicity and ferroptosis in vitro, and it suppressed SLC7A11 expression through H3K27me3 modification by EZH2. In addition, EZH2 inhibition or SLC7A11 overexpression attenuated the effects of HBx on D-GalN-induced ferroptosis in primary hepatocytes. The ferroptosis inhibitor ferrostatin-1 (Fer-1) protected against ALF and ferroptosis in vivo. By contrast, HBx exacerbates LPS/D-GalN-induced ALF and ferroptosis in HBx transgenic (HBx-Tg) mice.

Conclusion

HBx facilitates ferroptosis in ALF via EZH2/H3K27me3-mediated SLC7A11 suppression.

Complementary Roles of Cadaveric and Living Donor Liver Transplantation in Acute Liver Failure

BACKGROUND

Living donor liver transplantation may complement cadaveric transplantation in acute liver failure (ALF) patients.

METHODS

Between 2008 and 2017, 89 patients were treated for ALF; 15 patients (17%) recovered with intensive care treatment; 31 (35%) died without transplant. The records of the remaining 43 patients (median (range) age: 14 (1-62)) who underwent transplantation were evaluated.

RESULTS

The etiologic factors were toxic agents (10; mushrooms: 8; herbs: 2), hepatitis viruses (7; A: 1; B: 6), Wilson's disease (7), autoimmune hepatitis (4), and Budd-Chiari syndrome (2); 13 cases were idiopathic. Cadaveric organs (whole, split, reduced) were transplanted to 32 patients; 11 patients underwent living donor transplantation. One patient (2%) died of septic shock on the second postoperative day. Bacterial infection was the most common early (< 3 months) complication in the remaining patients (31/42; 74%), followed by delirium (5/42; 12%) and acute rejection requiring steroid pulse (5/42; 12%). Seven other patients died during median (range) follow-up of 94 (14-142) months: various infections (5), leukemia (1), and acute myocardial infarction (1). The 1-, 5-, and 10-year survival rates were 100%, 96%, and 92% in children and 94%, 82%, and 65% in adults respectively.

CONCLUSIONS

Cadaveric organ sharing and transplantation from living donors when appropriate yield a high survival rate, despite high early morbidity, in ALF patients whose conditions deteriorate despite intensive care treatment. Efforts to eliminate preventable causes of acute liver failure will lead to more efficient use of health care resources.

Inhibition of Drug-Induced Liver Injury in Mice Using a Positively Charged Peptide That Binds DNA

Hepatic cell death occurs in response to diverse stimuli such as chemical and physical damage. The exposure of intracellular contents such as DNA during necrosis induces a severe inflammatory response that has yet to be fully explored therapeutically. Here, we sought means to neutralize the ability of extracellular DNA to induce deleterious tissue inflammation when drug-induced liver injury had already ensued. DNA exposure and inflammation were investigated in vivo in drug-induced liver injury using intravital microscopy. The necrotic DNA debris was studied in murine livers in vivo and in DNA debris models in vitro by using a positively charged chemokine-derived peptide (MIG30; CXCL9[74-103]). Acetaminophen-induced liver necrosis was associated with massive DNA accumulation, production of CXC chemokines, and neutrophil activation inside the injured tissue. The MIG30 peptide bound the healthy liver vasculature and, to a much greater extent, to DNA-rich necrotic tissue. Moreover, MIG30 bound extracellular DNA directly in vivo in a charge-dependent manner and independently of glycosaminoglycans and chemokines. Post-treatment of mice with MIG30 reduced mortality, liver damage, and inflammation significantly. These effects were not observed with a control peptide that does not bind DNA. Mechanistically, MIG30 inhibited the interaction between DNA and histones, and promoted the dissociation of histones from necrotic debris. MIG30 also inhibited the pro-inflammatory effect of CpG DNA, as measured by a reduction in CXCL8 production, indicating that MIG30 disturbs the ability of DNA to induce hepatic inflammation. Conclusion: The use of DNA-binding peptides reduces necrotic liver injury and inflammation, even at late timepoints.

A Brief History of Hepatic Encephalopathy

Content available: Author Audio Recording.

Plasma Kallikrein as a Modulator of Liver Injury/Remodeling

The occurrence and persistence of hepatic injury which arises from cell death and inflammation result in liver disease. The processes that lead to liver injury progression and resolution are still not fully delineated. The plasma kallikrein-kinin system (PKKS) has been shown to play diverse functions in coagulation, tissue injury, and inflammation, but its role in liver injury has not been defined yet. In this study, we have characterized the role of the PKKS at various stages of liver injury in mice, as well as the direct effects of plasma kallikrein on human hepatocellular carcinoma cell line (HepG2). Histological, immunohistochemical, and gene expression analyses were utilized to assess cell injury on inflammatory and fibrotic factors. Acute liver injury triggered by carbon tetrachloride (CCl₄) injection resulted in significant upregulation of the plasma kallikrein gene (Klkb1) and was highly associated with the high mobility group box 1 gene, the marker of cell death (r = 0.75, p < 0.0005, n = 7). In addition, increased protein expression of plasma kallikrein was observed as clusters around necrotic areas. Plasma kallikrein treatment significantly increased the proliferation of CCl₄-induced HepG2 cells and induced a significant increase in the gene expression of the thrombin receptor (protease activated receptor-1), interleukin 1 beta, and lectin–galactose binding soluble 3 (galectin-3) (p < 0.05, n = 4). Temporal variations in the stages of liver fibrosis were associated with an increase in the mRNA levels of bradykinin receptors: beta 1 and 2 genes (p < 0.05; n = 3–10). In conclusion, these findings indicate that plasma kallikrein may play diverse roles in liver injury, inflammation, and fibrosis, and suggest that plasma kallikrein may be a target for intervention in the states of liver injury.

Oxidant Stress and Acetaminophen Hepatotoxicity: Mechanism-Based Drug Development

Significance: Acetaminophen (APAP) is one of the quantitively most consumed drugs worldwide. Although safe at therapeutic doses, intentional or unintentional overdosing occurs frequently causing severe liver injury and even liver failure. In the United States, 50% of all acute liver failure cases are caused by APAP overdose. However, only one antidote with a limited therapeutic window, N-acetylcysteine, is clinically approved. Thus, more effective therapeutic interventions are urgently needed. Recent Advances: Although APAP hepatotoxicity has been extensively studied for almost 50 years, particular progress has been made recently in two areas. First, there is now a detailed understanding of involvement of oxidative and nitrosative stress in the pathophysiology, with identification of the reactive species involved, their initial generation in mitochondria, amplification through the c-Jun N-terminal kinase pathway, and the mechanisms of cell death. Second, it was demonstrated in human hepatocytes and through biomarkers in vivo that the mechanisms of liver injury in animals accurately reflect the human pathophysiology, which allows the translation of therapeutic targets identified in animals to patients. Critical Issues: For progress, solid understanding of the pathophysiology of APAP hepatotoxicity and of a drug's targets is needed to identify promising new therapeutic intervention strategies and drugs, which may be applied to humans. Future Directions: In addition to further refine the mechanistic understanding of APAP hepatotoxicity and identify additional drugs with complementary mechanisms of action to prevent cell death, more insight into the mechanisms of regeneration and developing of drugs, which promote recovery, remains a future challenge. Antioxid. Redox Signal. 35, 718-733.

Acute liver failure due to herpes simplex virus: diagnostic clues and potential role of plasmapheresis: A case report

INTRODUCTION

Acute liver failure (ALF) is a life-threatening condition that remains challenging for physicians despite several advances in supportive care. Etiologies vary worldwide, with herpes simplex virus (HSV) hepatitis representing less than 1% of cases. Despite its low incidence, ALF is a lethal cause of acute necrotizing hepatitis and has a high mortality. Early antiviral treatment is beneficial for survival and decreased liver transplantation necessity. However, plasmapheresis, despite its theoretical potential benefit, is scarcely reported.

PATIENT CONCERNS

A 25-year-old woman with no known disease presented with painful pharynx ulcers, increased transaminases and impaired liver function.

DIAGNOSIS

ALF due to a disseminated HSV-2 primary infection was diagnosed with a positive polymerase chain reaction for HSV-2 in the biopsied liver tissue and blood.

INTERVENTIONS

Empiric antiviral treatment was initiated. After clinical deterioration, plasmapheresis was also initiated.

OUTCOMES

After 6 cycles of plasmapheresis and supportive care, the patient's condition improved without undergoing liver transplantation.

CONCLUSIONS

ALF is a life-threatening condition, and HSV as an etiology must be suspected based on background, clinical manifestation, and laboratory information. The potential role of plasmapheresis in HSV hepatitis should be considered.

Using an Automated Algorithm to Identify Potential Drug-Induced Liver Injury Cases in a Pharmacovigilance Database

INTRODUCTION

Drug-induced liver injury (DILI) is the most frequent cause of acute liver failure in North America and Europe, but it is often missed because of unstandardized diagnostic methods and criteria. This study aimed to develop and validate an automated algorithm to identify potential DILI cases in routine pharmacovigilance (PV) activities.

METHODS

Post-marketing hepatic adverse events reported for a potentially hepatotoxic drug in a global PV database from 19 March 2017 to 18 June 2018 were assessed manually and with the automated algorithm. The algorithm provided case assessments by applying pre-specified criteria to all case data and narratives simultaneously.

RESULTS

A total of 1456 cases were included for analysis and assessed manually. Sufficient data for algorithm assessment were available for 476 cases (32.7%). Of these cases, manual assessment identified 312 (65.5%) potential DILI cases while algorithm assessment identified 305 (64.1%) potential DILI cases. Comparison of manual and algorithm assessments demonstrated a sensitivity of 97.8% and a specificity of 79.3% for the algorithm. Given the prevalence of potential DILI cases in the population studied, the algorithm was calculated to have positive predictive value 56.3% and negative predictive value 99.2%. The time required for manual review compared to algorithm review suggested that application of the algorithm prior to manual screening would have resulted in a time savings of 42.2%.

CONCLUSION

An automated algorithm to identify potential DILI cases was developed and successfully implemented. The algorithm demonstrated a high sensitivity, a high negative predictive value, along with significant efficiency and utility in a real-time PV database.

Nicotinic Acid against Acetaminophen-Induced Hepatotoxicity via Sirt1/Nrf2 Antioxidative Pathway in Mice

Acetaminophen (N-acetyl-p-aminophenol, APAP) overdose causes hepatotoxicity, even liver failure, and oxidative stress plays pivotal role in its pathogenesis. Nicotinic acid (NA) is one form of vitamin B3, which has been used to treat a series of diseases in clinic for decades. To date, several studies have evidenced that NA has anti-oxidative property. Therefore, NA may have the hepatoprotective potential against APAP-induced toxicity. Here, our aim was to investigate the beneficial effect of NA against hepatotoxicity induced by APAP and its mechanism in vivo. BALB/c mice were intraperitoneally injected with NA (100 mg/kg) 3 times at 24, 12 and 1 h before APAP (600 mg/kg or 400 mg/kg) challenge. The results showed that pretreatment of NA markedly improved the survival rate, alleviated serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels and mitigated the histopathological injuries compared to APAP-exposed mice. Furthermore, NA significantly elevated the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) content, while reduced malondialdehyde (MDA) level. Finally, the signaling pathway was probed. The western blot revealed that NA up-regulated Sirtuin1 (Sirt1), nuclear factor erythroid 2-related factor 2 (Nrf2) and NAD(P)H quinone dehydrogenase-1 (NQO-1) expression and down-regulated Kelch-like ECH-associated protein 1 (Keap1) level in liver followed APAP exposure, implying Sirt1/Nrf2 axis exerted an essential role in the protective mechanism of NA on APAP toxicity. In brief, pretreatment of NA effectively protects liver against hepatotoxicity due to overdose of APAP through an antioxidant dependent manner modulated by Sirt1/Nrf2 signaling pathway.

Protective Role of 4-Octyl Itaconate in Murine LPS/D-GalN-Induced Acute Liver Failure via Inhibiting Inflammation, Oxidative Stress, and Apoptosis

Oxidative stress, inflammation, and apoptosis are crucial in the pathogenesis of acute liver failure (ALF). 4-Octyl itaconate (OI) showed antioxidative and anti-inflammatory properties in many disease models. However, its role in lipopolysaccharide- (LPS-)/D-galactosamine- (D-GalN-) induced ALF is still not investigated. Here, we established an ALF murine model induced by LPS/D-GalN administration. And we found that OI improved survival rate in the murine ALF model. Our results also showed that OI alleviated LPS/D-GalN-induced hepatic histopathological injury and reduced the serum activities of alanine transaminase and aspartate transaminase. Moreover, OI reduced serum levels of proinflammatory cytokines such as monocyte chemotactic protein-1, tumor necrosis factors-α, and interlukin-6. Additionally, OI mitigated oxidative stress and alleviated lipid peroxidation in a murine model of ALF. This was evaluated by a reduction of thiobarbituric acid reactive substances (TBARS) in liver tissues. In addition, OI increased the ratio of reduced glutathione/oxidized glutathione and the activities of antioxidant enzymes including catalase and superoxide dismutase. Moreover, the apoptosis of hepatocytes in the liver was inhibited by OI. Furthermore, we found that OI inhibited LPS-induced nuclear translocation and activation of factor-kappa B (NF-κB) p65 in macrophages which could be inhibited by OI-induced activation of nuclear factor erythroid-2-related factor (Nrf2) signaling. Additionally, D-GalN-induced reactive oxygen species (ROS) generation and apoptosis in hepatocytes were inhibited by OI-induced activation of Nrf2 signaling. Therefore, the underlying mechanism for OI's protective effect in LPS/D-GalN-induced ALF may be associated with deactivation of NF-κB signaling in macrophages to reduce inflammation and inhibition of ROS-related hepatocyte apoptosis by activating Nrf2. In conclusion, OI showed a protective role in LPS/D-GalN-induced ALF by reducing inflammation, enhancing antioxidant capacity, and inhibiting cell apoptosis.

Therapeutic plasma exchange in liver failure

The multi-organ failure syndrome associated with acute and acute-on-chronic liver failure (ACLF) is thought to be mediated by overwhelming systemic inflammation triggered by both microbial and non-microbial factors. Therapeutic plasma exchange (TPE) has been proven to be an efficacious therapy in autoimmune conditions and altered immunity, with more recent data supporting its use in the management of liver failure. Few therapies have been shown to improve survival in critically ill patients with liver failure who are not expected to survive until liver transplantation (LT), who are ineligible for LT or who have no access to LT. TPE has been shown to reduce the levels of inflammatory cytokines, modulate adaptive immunity with the potential to lessen the susceptibility to infections, and reduce the levels of albumin-bound and water-bound toxins in liver failure. In patients with acute liver failure, high volume TPE has been shown to reduce the vasopressor requirement and improve survival, particularly in patients not eligible for LT. Standard volume TPE has also been shown to reduce mortality in certain sub-populations of patients with ACLF. TPE may be most favorably employed as a bridge to LT in patients with ACLF. In this review, we discuss the efficacy and technical considerations of TPE in both acute and acute-on-chronic liver failure.

Short-Term Safety of Repeated Acetaminophen Use in Patients With Compensated Cirrhosis

Current guidelines recommend restricting acetaminophen (APAP) use in patients with cirrhosis, but evidence to support that recommendation is lacking. Prior studies focused on pharmacokinetics (PK) of APAP in cirrhosis but did not rigorously examine clinical outcomes, sensitive biomarkers of liver damage, or serum APAP‐protein adducts, which are a specific marker of toxic bioactivation. Hence, the goal of this pilot study was to test the effects of regularly scheduled APAP dosing in a well‐defined compensated cirrhosis group compared to control subjects without cirrhosis, using the abovementioned outcomes. After a 2‐week washout, 12 subjects with and 12 subjects without cirrhosis received 650 mg APAP twice per day (1.3 g/day) for 4 days, followed by 650 mg on the morning of day 5. Patients were assessed in‐person at study initiation (day 1) and on days 3 and 5. APAP‐protein adducts and both conventional (alanine aminotransferase) and sensitive (glutamate dehydrogenase [GLDH], full‐length keratin 18 [K18], and total high‐mobility group box 1 protein) biomarkers of liver injury were measured in serum on the mornings of days 1, 3, and 5, with detailed PK analysis of APAP, metabolites, and APAP‐protein adducts throughout day 5. No subject experienced adverse clinical outcomes. GLDH and K18 were significantly different at baseline but did not change in either group during APAP administration. In contrast, clearance of APAP‐protein adducts was dramatically delayed in the cirrhosis group. Minor differences for other APAP metabolites were also detected. Conclusion: Short‐term administration of low‐dose APAP (650 mg twice per day, <1 week) is likely safe in patients with compensated cirrhosis. These data provide a foundation for future studies to test higher doses, longer treatment, and subjects who are decompensated, especially in light of the remarkably delayed adduct clearance in subjects with cirrhosis.

Puerarin Prevents Acute Liver Injury via Inhibiting Inflammatory Responses and ZEB2 Expression

Puerarin, an isoflavone component extracted from herb radix puerariae, is widely used in China in the treatment of immune diseases and inflammation. Previous studies have demonstrated that puerarin prevented acute lung injury by regulating inflammatory responses. However, the effect of puerarin on acute liver injury (ALI) was unclear. The purpose of this study was to explore the beneficial effects of puerarin when applied to ALI. We found that puerarin inhibited liver injury and inflammatory cell infiltration in lipopolysaccharide (LPS)/D-galactose (D-Gal)-induced acute liver failure and the liver pro-inflammatory cytokines interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha (TNF-α) in liver tissues with ALI and LPS-induced L-02 cells but upregulated the expression level of zinc finger E-box-binding homeobox 2 (ZEB2). Significantly, the results of this study showed that the inhibition of liver pro-inflammatory cytokine (IL-1β, IL-6, and TNF-α) production in LPS-induced L-02 cells was caused by ZEB2 overexpression. However, knocking down ZEB2 promoted LPS-mediated secretion of liver pro-inflammatory cytokines in L-02 cells. Additional experiments showed that puerarin inhibited the activation of the NF-κB signaling pathway by elevating ZEB2 expression in L-02 cells. In summary, puerarin most likely prevented activation of the pro-inflammatory factors and reduced LPS/D-Gal-induced liver injury by enhancing the ZEB2 expression level and, consequently, blocking activation of the NF-κB signaling pathway in the liver.

Delayed administration of N-acetylcysteine blunts recovery after an acetaminophen overdose unlike 4-methylpyrazole

N-acetylcysteine (NAC) is the only clinically approved antidote against acetaminophen (APAP) hepatotoxicity. Despite its efficacy in patients treated early after APAP overdose, NAC has been implicated in impairing liver recovery in mice. More recently, 4-methylpyrazole (4MP, Fomepizole) emerged as a potential antidote in the mouse APAP hepatotoxicity model. The objective of this manuscript was to verify the detrimental effect of NAC and its potential mechanism and assess whether 4MP has the same liability. C57BL/6J mice were treated with 300 mg/kg APAP; 9h after APAP and every 12h after that, the animals received either 100 mg/kg NAC or 184.5 mg/kg 4MP. At 24 or 48h after APAP, parameters of liver injury, mitochondrial biogenesis and cell proliferation were evaluated. Delayed NAC treatment had no effect on APAP-induced liver injury at 24h but reduced the decline of plasma ALT activities and prevented the shrinkage of the areas of necrosis at 48h. This effect correlated with down-regulation of key activators of mitochondrial biogenesis (AMPK, PGC-1α, Nrf1/2, TFAM) and reduced expression of Tom 20 (mitochondrial mass) and PCNA (cell proliferation). In contrast, 4MP attenuated liver injury at 24h and promoted recovery at 48h, which correlated with enhanced mitochondrial biogenesis and hepatocyte proliferation. In human hepatocytes, 4MP demonstrated higher efficacy in preventing cell death compared to NAC when treated at 18h after APAP. Thus, due to the wider treatment window and lack of detrimental effects on recovery, it appears that at least in preclinical models, 4MP is superior to NAC as an antidote against APAP overdose.

Deciphering the Dynamic Complexities of the Liver Microenvironment - Toward a Better Understanding of Immune-Mediated liver Injury Caused by Immune Checkpoint Inhibitors (ILICI)

Immune checkpoint inhibitors (ICIs) represent a promising therapy for many types of cancer. However, only a portion of patients respond to this therapy and some patients develop clinically significant immune-mediated liver injury caused by immune checkpoint inhibitors (ILICI), an immune-related adverse event (irAE) that may require the interruption or termination of treatment and administration of systemic corticosteroids or other immunosuppressive agents. Although the incidence of ILICI is lower with monotherapy, the surge in combining ICIs with chemotherapy, targeted therapy, and combination of different ICIs has led to an increase in the incidence and severity of ILICI - a major challenge for development of effective and safe ICI therapy. In this review, we highlight the importance and contribution of the liver microenvironment to ILICI by focusing on the emerging roles of resident liver cells in modulating immune homeostasis and hepatocyte regeneration, two important decisive factors that dictate the initiation, progression, and recovery from ILICI. Based on the proposed contribution of the liver microenvironment on ICILI, we discuss the clinical characteristics of ILICI in patients with preexisting liver diseases, as well as the challenges of identifying prognostic biomarkers to guide the clinical management of severe ILICI. A better understanding of the liver microenvironment may lead to novel strategies and identification of novel biomarkers for effective management of ILICI.

Early use of dexamethasone increases Nr4a1 in Kupffer cells ameliorating acute liver failure in mice in a glucocorticoid receptor-dependent manner

BACKGROUND AND OBJECTIVE

Acute liver failure (ALF) is a type of disease with high mortality and rapid progression with no specific treatment methods currently available. Glucocorticoids exert beneficial clinical effects on therapy for ALF. However, the mechanism of this effect remains unclear and when to use glucocorticoids in patients with ALF is difficult to determine. The purpose of this study was to investigate the specific immunological mechanism of dexamethasone (Dex) on treatment of ALF induced by lipopolysaccharide (LPS)/D-galactosamine (D-GaIN) in mice.

METHODS

Male C57BL/6 mice were given LPS and D-GaIN by intraperitoneal injection to establish an animal model of ALF. Dex was administrated to these mice and its therapeutic effect was observed. Hematoxylin and eosin (H&E) staining was used to determine liver pathology. Multicolor flow cytometry, cytometric bead array (CBA) method, and next-generation sequencing were performed to detect changes of messenger RNA (mRNA) in immune cells, cytokines, and Kupffer cells, respectively.

RESULTS

A mouse model of ALF can be constructed successfully using LPS/D-GaIN, which causes a cytokine storm in early disease progression. Innate immune cells change markedly with progression of liver failure. Earlier use of Dex, at 0 h rather than 1 h, could significantly improve the progression of ALF induced by LPS/D-GaIN in mice. Numbers of innate immune cells, especially Kupffer cells and neutrophils, increased significantly in the Dex-treated group. In vivo experiments indicated that the therapeutic effect of Dex is exerted mainly via the glucocorticoid receptor (Gr). Sequencing of Kupffer cells revealed that Dex could increase mRNA transcription level of nuclear receptor subfamily 4 group A member 1 (Nr4a1), and that this effect disappeared after Gr inhibition.

CONCLUSIONS

In LPS/D-GaIN-induced ALF mice, early administration of Dex improved ALF by increasing the numbers of innate immune cells, especially Kupffer cells and neutrophils. Gr-dependent Nr4a1 upregulation in Kupffer cells may be an important ALF effect regulated by Dex in this process.

Rodenticide-induced acute liver failure - Uncommon presentation of commonly available poison

Rodenticide or 'rat poison' is easily available in a predominantly agrarian economy such as India. Metal phosphides or yellow phosphorous are two common rodenticides. Acute liver failure caused by accidental or suicidal poisoning with rodenticides has been infrequently reported in literature. Liver transplantation offers the best chances of survival in severe intoxication. However, the availability of liver transplantation in resource-limited settings presents a challenge. N-acetyl cysteine has been successfully used in paracetamol poisoning. Its use in rodenticide-induced acute liver failure is not so well known. We report three cases of rodenticide-related acute liver failure, one of them being a pregnant lady. All three patients were given N-acetyl cysteine and two patients improved. It is possible that the administration of N-acetyl cysteine contributed to the improvement in these two.

Molecular mechanisms and therapeutic implications of dihydromyricetin in liver disease

Recent studies demonstrated that dihydromyricetin (DHM) has prominent therapeutic effects on liver injury and liver cancer. By summarizing the current preclinical in vitro and in vivo studies, the present review examines the preventive and therapeutic effects of DHM on liver disorders as well as its potential mechanisms. Briefly, in both chemical- and alcohol-induced liver injury models, DHM ameliorates hepatocyte necrosis and steatosis while promoting liver regeneration. In addition, DHM can alleviate nonalcoholic fatty liver disease (NAFLD) via regulating lipid/glucose metabolism, probably due to its anti-inflammatory or sirtuins-dependent mechanisms. Furthermore, DHM treatment inhibits cell proliferation, induces apoptosis and autophagy and regulates redox balance in liver cancer cells, thus exhibiting remarkable anti-cancer effects. The pharmacological mechanisms of DHM may be associated with its anti-inflammatory, anti-oxidative and apoptosis-regulatory benefits. With the accumulating interests in utilizing natural products to target common diseases, our work aims to improve the understanding of DHM acting as a novel drug candidate for liver diseases and to accelerate its translation from bench to bedside.

Safety of treating acute liver injury and failure

INTRODUCTION

Acute liver injury and progression to acute liver failure can be life-threatening conditions that require prompt careful clinical assessment and therapeutic management.

AREAS COVERED

The aim of this article is to review the safety and side effect profile of pharmacological therapies used in the treatment of acute liver injury with specific focus on hepatic toxicity. We performed an extensive literature search with the terms 'acute liver injury,' 'acute liver failure,' 'therapy,' 'safety,' 'adverse reactions' and 'drug induced liver injury.' A thorough discussion of the main drugs and devices used in patients with acute liver injury and acute liver failure, its safety profile and the management of complications associated to therapy of these conditions is presented.

EXPERT OPINION

Several pharmacological approaches are used in acute liver injury and acute liver failure in an empirical basis. Whilst steroids are frequently tried in serious drug-induced liver injury there is concern on a potential harmful effect of these agents because of the higher mortality in patients receiving the drug; hence, statistical approaches such as propensity score matching might help resolve this clinical dilemma. Likewise, properly designed clinical trials using old and new drugs for subjects with serious drug-induced liver injury are clearly needed.

Study protocol: epidemiological and clinical characteristics of acute viral hepatitis in Brazilian health services

INTRODUCTION

Acute viral hepatitis is a disease of great clinical importance. This study proposes actions to better characterise cases of acute hepatitis in Brazil and to provide relevant information to institutionalised health policies within the Unified Health System. Available data on acute hepatitis in Brazil need to be re-evaluated regarding the different hepatotropic agent (hepatitis A to E virus) frequencies, as well as other agents that can cause similar clinical conditions, such as Herpes Simplex Virus 1 and 2(HSV1, HSV2), Varicella Zoster Virus (VZV), Cytomegalovirus (CMV), Epstein Barr Virus (EBV), Human Herpes Virus 6 and 7 (HHV6, HHV7), arbovirus (yellow fever, dengue, chikungunya, Zika), parvovirus B19, adenovirus, parechovirus, enterovirus, HIV, leptospirosis, toxoplasmosis and syphilis, in addition to autoimmune hepatitis. In this context, the primary aim of this study is the clinical-epidemiological and molecular characterisation of acute viral hepatitis in Brazilian health services from all geographical regions of the country. The present article describes the study protocol.

METHODS AND ANALYSIS

This study will evaluate 2280 patients with symptoms and/or signs suggestive of acute liver disease in Brazilian health institutions in all five geographic Brazilian regions. Demographic, epidemiological and clinical data will be collected, as well as blood samples to be analysed at Hospital Israelita Albert Einstein Clinical Laboratory.

ETHICS AND DISSEMINATION

Ethics approval was obtained at the national research ethics committee (Conselho Nacional de Ética em Pesquisa- CONEP-CAAE 00952818.4.1001.0071) and at all participating sites. Results will be published in journals and presented at scientific meetings.

Acute (fulminant) liver failure: a clinical and imaging review

Acute liver failure (ALF) is a rare clinical entity with high morbidity and mortality frequently requiring liver transplantation for survival. Imaging, particularly with ultrasound, plays an important role, especially to distinguish patients with underlying chronic liver disease who have lower transplant priority. We discuss the clinical and imaging findings in the three subtypes of ALF using a multi-modality approach with an emphasis on ultrasound.

Design and Usability Evaluations of a 3D-Printed Implantable Drug Delivery Device for Acute Liver Failure in Preclinical Settings

Acute liver failure (ALF) requiring liver transplantation is a disease that occurs due to rapid hepatocellular dysfunction. As liver transplantation has various limitations, including donor scarcity, high cost, and immuno-incompatibility, continuous local delivery of biopharmaceuticals to the liver tissue can be a promising ALF treatment option. Here, the in vivo safety and usability of a 3D-printed implantable drug delivery device for effective ALF treatment is evaluated. The implantable reservoir consists of a 3D-printed container and a semipermeable membrane for repeated administrations of drugs, specifically to the liver tissue. The physical stability and function of the 3D-printed reservoir are confirmed by the mechanical properties and in vitro drug release test, respectively. In mice implanted with the reservoir system, mortality, weight changes, clinical signs, hematological and serum biochemical changes, and organ weight changes are not observed, suggesting no foreign body reaction. The usability of the reservoir system is further evaluated using an ALF model of 70% hepatectomized mice treated with N-acetylcysteine through the system, showing cell-specific regeneration and significant liver injury alleviation. Overall, the 3D-printed reservoir system is safe for studying the therapeutic potential of ALF treatment, and it can be used for the delivery of various active pharmaceutical ingredients.

An extracorporeal bioartificial liver embedded with 3D-layered human liver progenitor-like cells relieves acute liver failure in pigs

Clinical advancement of the bioartificial liver is hampered by the lack of expandable human hepatocytes and appropriate bioreactors and carriers to encourage hepatic cells to function during extracorporeal circulation. We have recently developed an efficient approach for derivation of expandable liver progenitor-like cells from human primary hepatocytes (HepLPCs). Here, we generated immortalized and functionally enhanced HepLPCs by introducing FOXA3, a hepatocyte nuclear factor that enables potentially complete hepatic function. When cultured on macroporous carriers in an air-liquid interactive bioartificial liver (Ali-BAL) support device, the integrated cells were alternately exposed to aeration and nutrition and grew to form high-density three-dimensional constructs. This led to highly efficient mass transfer and supported liver functions such as albumin biosynthesis and ammonia detoxification via ureagenesis. In a porcine model of drug overdose-induced acute liver failure (ALF), extracorporeal Ali-BAL treatment for 3 hours prevented hepatic encephalopathy and led to markedly improved survival (83%, n = 6) compared to ALF control (17%, n = 6, P = 0.02) and device-only (no-cell) therapy (0%, n = 6, P = 0.003). The blood ammonia concentrations, as well as the biochemical and coagulation indices, were reduced in Ali-BAL-treated pigs. Ali-BAL treatment attenuated liver damage, ameliorated inflammation, and enhanced liver regeneration in the ALF porcine model and could be considered as a potential therapeutic avenue for patients with ALF.

Liver transplantation in acute liver failure: Dilemmas and challenges

Acute liver failure (ALF) refers to a state of severe hepatic injury that leads to altered coagulation and sensorium in the absence of pre-existing liver disease. ALF has different causes, but the clinical characteristics are strikingly similar. In clinical practice, however, inconsistency in the definition of ALF worldwide and confusion regarding the existence of pre-existing liver disease raise diagnostic dilemmas. ALF mortality rates used to be over 80% in the past; however, survival rates on medical treatment have significantly improved in recent years due to a greater understanding of pathophysiology and advances in critical care management. The survival rates in acetaminophen-associated ALF have become close to the post-transplant survival rates. Given that liver transplantation (LT) is an expensive treatment that involves a major surgical operation in critically ill patients and lifelong immunosuppression, it is very important to select accurate patients who may benefit from it. Still, emergency LT remains a lifesaving procedure for many ALF patients. However, there is a lack of consistency in current prognostic models that hampers the selection of transplant candidates in a timely and precise manner. The other problems associated with LT in ALF are the shortage of graft, development of contraindications on the waiting list, vaguely defined delisting criteria, time constraints for pre-transplant evaluation, ethical concerns, and comparatively poor post-transplant outcomes in ALF. Therefore, there is a desperate need to establish accurate prognostic models and explore the roles of evolving adjunctive and alternative therapies, such as liver support systems, plasma exchange, stem cells, auxiliary LT, and so on, to enhance transplant-free survival and to fill the void created by the graft shortage

Role of Noncoding RNAs in Acetaminophen-Induced Liver Injury

Genomic and transcriptomic analyses have well established that the major fraction of the mammalian genome is transcribed into different classes of RNAs ranging in size from a few nucleotides to hundreds of thousands of nucleotides, which do not encode any protein. Some of these noncoding RNAs (ncRNAs) are directly or indirectly linked to the regulation of expression or functions of 25,000 proteins coded by <2% of the human genome. Among these regulatory RNAs, microRNAs are small (2125 nucleotides) RNAs that are processed from precursor RNAs that have stemloop structure, whereas noncoding RNAs >200 nucleotides are termed long noncoding RNAs (lncRNAs). Circular RNAs (circRNAs) are newly identified lncRNA members that are generated by back-splicing of primary transcripts. The functions of ncRNAs in modulating liver toxicity of xenobiotics are emerging only recently. Acetaminophen (N-acetyl-para-aminophenol, paracetamol or APAP) is a safe analgesic and antipyretic drug at the therapeutic dose. However, it can cause severe liver toxicity that may lead to liver failure if overdosed or combined with alcohol, herbs, or other xenobiotics. This review discusses the role of ncRNAs in acetaminophen metabolism, toxicity, and liver regeneration after APAP-induced liver injury (AILI).

Fiber scaffold bioartificial liver therapy relieves acute liver failure and extrahepatic organ injury in pigs

Rationale: Acute liver failure (ALF) causes severe liver injury and a systemic inflammatory response, leading to multiorgan failure with a high short-term mortality. Bioartificial liver (BAL) therapy is a promising approach that is hampered by the lack of appropriate bioreactors and carriers to retain hepatic cell function and poor understanding of BAL treatment mechanisms in ALF and extrahepatic organ injury. Recently, we used a fiber scaffold bioreactor (FSB) for the high-density, three-dimensional (3D) culture of primary porcine hepatocytes (PPHs) combined with an absorption component to construct a BAL and verified its function in a D-galactosamine (D-gal)-induced ALF porcine model to evaluate its protective effects on the liver and extrahepatic organs. Methods: Male pigs were randomized into standard/supportive therapy (ST), ST+no-cell BAL (ST+Sham BAL) and ST+BAL groups and received treatment 48 h after receiving a D-gal injection. Changes in blood chemistry and clinical symptoms were monitored for 120 h. Tissues and plasma were collected for analysis by pathological examination, immunoblotting, quantitative PCR and immunoassays. Results: PPHs cultured in the FSB obtained sufficient aeration and nutrition for high-density, 3D culture and maintained superior viability and functionality (biosynthesis and detoxification) compared with those cultured in flasks. All the animals developed ALF, acute kidney injury (AKI) and hepatic encephalopathy (HE) 48 h after D-gal infusion and received corresponding therapies. Animals in the BAL group showed markedly improved survival (4/5; 80%) compared with those in the ST+Sham BAL (0/5; p < 0.001) and ST (0/5; p < 0.001) groups. The levels of blood ammonia and biochemical and inflammatory indices were alleviated after BAL treatment. Increased liver regeneration and attenuations in the occurrence and severity of ALF, AKI and HE were observed in the ST+BAL group compared with the ST (p = 0.0009; p = 0.038) and ST+Sham BAL (p = 0.011; p = 0.031) groups. Gut leakage, the plasma endotoxin level, bacterial translocation, and peripheral and neuroinflammation were alleviated in the ST+BAL group compared with those in the other groups. Conclusions: BAL treatment enhanced liver regeneration and alleviated the systemic inflammatory response and extrahepatic organ injury to prolong survival in the ALF model and has potential as a therapeutic approach for ALF patients.

Population pharmacokinetics of immediate-release and modified-release paracetamol and its major metabolites in a supratherapeutic dosing study

OBJECTIVES

Overdose with paracetamol modified-release (MR) formulation, a bilayer tablet containing 69% slow-release component, has been increasing since its introduction to the market. However, little evidence exists for the management of MR paracetamol overdose. We aimed to develop a population pharmacokinetic (PK) model for immediate-release (IR) and MR paracetamol and its major metabolism, and quantitatively understand the formulation difference in toxicity assessment based on the nomogram line.

METHODS

Data from a cross-over study design in nine healthy volunteers administered a single supratherapeutic oral dose (80 mg/kg) of either IR and MR paracetamol were available from a published study. Plasma concentrations for paracetamol and its metabolites glucuronide (APAPG) and sulfate conjugate (APAPS) for both formulations were measured and analysed with population pharmacokinetic (PK) method using NONMEM. Toxicity in both formulations was assessed by comparing the simulated paracetamol concentrations under different paracetamol dose levels with the 150 mg/L nomograms. The difference in the assessment was compared between the two formulations.

RESULTS

Paracetamol concentrations for the IR formulation were described with a two-compartment model with first-order input and a lag time. The delayed time-course of MR paracetamol concentrations was best captured by a parallel absorption model in which the slow-release component was a serial zero-order then the first-order process. The formation of APAPG was linear, while APAPS concentrations were best fitted by a Michaelis-Menten process. The relative bioavailability of MR paracetamol compared to IR (FMR/IR) was estimated as 0.81. The simulated probability of making different toxicity assessments based on nomogram line was increased with dose levels and was as high as 14.6% after 22 g IR or MR paracetamol ingested.

CONCLUSIONS

A joint parent-metabolite model to describe time-course profiles of both IR and MR paracetamol and its metabolites APAPG and APAPS concentrations was developed. Simulations from the model showed that toxicity assessment based on the 150 mg/L nomograms is not suitable in MR paracetamol overdoses.

Acute Liver Failure From Sickle Cell Hepatopathy Treated With Exchange Transfusion

Sickle cell disease (SCD) is a qualitative hemoglobinopathy that can cause widespread sickling and vaso-occlusive events in all organ systems. Sickle cell hepatopathy is an umbrella term for various acute and chronic pathologies of the liver as a result of sickling in SCD patients. We present below the case of a 49-year-old woman who had an acute liver failure in the setting of a hepatic crisis with recovery after exchange transfusion. Hepatic involvement in SCD may be life-threatening. Understanding the etiology and severity of hepatic involvement by sickling is necessary for appropriate treatment.

Gut Microbiota and Chemical-Induced Acute Liver Injury

Background: Drug overdose or chemical exposures are the main causes of acute liver injury (ALI). Severe liver injury can develop into liver failure that is an important cause of liver-related mortality in intensive care units in most countries. Pharmacological studies have utilized a variety of comprehensive chemical induction models that recapitulate the natural pathogenesis of acute liver injury. Their mechanism is always based on redox imbalance-induced direct hepatotoxicity and massive hepatocyte cell death, which can trigger immune cell activation and recruitment to the liver. However, the pathogenesis of these models has not been fully stated. Many studies showed that gut microbiota plays a crucial role in chemical-induced liver injury. Hepatotoxicity is likely induced by imbalanced microbiota homeostasis, gut mucosal barrier damage, systemic immune activation, microbial-associated molecular patterns, and bacterial metabolites. Meanwhile, many preclinical studies have shown that supplementation with probiotics can improve chemical-induced liver injury. In this review, we highlight the pathogenesis of gut microorganisms in chemical-induced acute liver injury animal models and explore the protective mechanism of exogenous microbial supplements on acute liver injury.

Verapamil inhibits early acute liver failure through suppressing the NLRP3 inflammasome pathway

Acute liver failure (ALF) is a rare disease characterized by the sudden onset of serious hepatic injury, as manifested by a profound liver dysfunction and hepatic encephalopathy in patients without prior liver disease. In this paper, we aim to investigate whether verapamil, an antagonist of TXNIP, inhibits early ALF through suppressing the NLRP3 inflammasome pathway. Firstly, an ALF mouse model was induced by lipopolysaccharide (LPS)/D-galactosamine (GalN) treatment. The optimal concentration of verapamil in treating early ALF mice was determined followed by investigation on its mechanism in LPS/GalN-induced liver injury. Western blot analysis and co-immunoprecipitation were performed to determine the activation of the TXNIP/NLRP3 inflammasome pathway. Subsequently, overexpression of NLRP3 in mouse liver was induced by transfection with AAV-NRLP3 in vivo and in vitro to identity whether verapamil inhibited early ALF through suppressing the activation of NLRP3 inflammasome. We found that ALF was induced by LPS/GalN in mice but was alleviated by verapamil through a mechanism that correlated with suppression of the NLRP3 inflammasome pathway. Oxidative stress and inflammatory response were induced by intraperitoneal injection of LPS/GalN, but alleviated with injection of verapamil. Overexpression of NLRP3 via AAV in mouse liver in vivo and in vitro reduced the therapeutic effect of verapamil on LPS/GalN-induced ALF. Taken together, the TXNIP antagonist verapamil could inhibit activation of the NLRP3 inflammasome, inflammatory responses and oxidative stress to alleviate LPS/GalN-induced ALF.

Successful elimination of bilirubin in critically ill patients with acute liver dysfunction using a cytokine adsorber and albumin dialysis: a pilot study

There are different methods of artificial liver support for patients with acute liver dysfunction (ALD). However, CytoSorb (CS) might be a new approved option for those patients. Question of interest is whether the elimination performance of CS was comparable to that of advanced organ support (ADVOS). Patients, treated with CS (integrated into high-flux dialysis) or ADVOS and a total bilirubin > 10 mg/dl were included. Laboratory parameters were evaluated before starting therapy (d0) and 12–24 h thereafter (d1). The Wilcoxon-test with associated samples was used for statistical analysis. Thirty-nine patients (33 CS, 6 ADVOS) were included. The median bilirubin at d0 was 16.9 and 17.7 mg/dl and at d1 was 13.2 and 15.9 mg/dl, in the CS and ADVOS group, respectively. There was a significant bilirubin reduction as well in the CS group (p < 0.001, median relative reduction: 22.5%) as in the ADVOS group (p = 0.028, median relative reduction: 22.8%). There was no significant difference in the relative bilirubin reduction between CS and ADVOS therapies. The use of CytoSorb and ADVOS in patients with ALD led to a significant and comparable decrease in total bilirubin. The easy use of CS might be an advantage compared to other procedures.

Cell and Tissue Therapy for the Treatment of Chronic Liver Disease

Liver disease is an important clinical problem, impacting 600 million people worldwide. It is the 11th-leading cause of death in the world. Despite constant improvement in treatment and diagnostics, the aging population and accumulated risk factors led to increased morbidity due to nonalcoholic fatty liver disease and steatohepatitis. Liver transplantation, first established in the 1960s, is the second-most-common solid organ transplantation and is the gold standard for the treatment of liver failure. However, less than 10% of the global need for liver transplantation is met at the current rates of transplantation due to the paucity of available organs. Cell- and tissue-based therapies present an alternative to organ transplantation. This review surveys the approaches and tools that have been developed, discusses the distinctive challenges that exist for cell- and tissue-based therapies, and examines the future directions of regenerative therapies for the treatment of liver disease.

Vitamin D deficiency exacerbates hepatic oxidative stress and inflammation during acetaminophen-induced acute liver injury in mice

Several experiments confirmed that vitamin D3 protected against acetaminophen (APAP)-induced acute liver injury (ALI). This research aimed to evaluate the influence of vitamin D deficiency (VDD) on APAP-induced ALI. In VDD and VDD + APAP groups, mice were fed with VDD diet. In APAP and VDD + APAP groups, mice were intraperitoneally injected with a sublethal dose of APAP (150 mg/kg). A sublethal dose of APAP caused a slight elevation of ALT and AST. Interestingly, APAP-induced elevation of ALT and AST was aggravated in VDD-fed mice. APAP-induced hepatic necrosis was exacerbated in VDD-fed mice. In addition, APAP-induced hepatocyte death, measured using TUNEL assay, was exacerbated in VDD-fed mice. Additional experiment showed that APAP-induced hepatic GSH depletion and lipid peroxidation were exacerbated in VDD-fed mice. Moreover, APAP-induced upregulation of antioxidant genes, such as hepatic heme oxygenase-1 (Ho-1), glutathione peroxidase (Gshpx), superoxide dismutase 1 (Sod1) and catalase enzymes (Cat), was aggravated in VDD-fed mice. Although a sublethal dose of APAP did not cause hepatic inflammation, hepatic proinflammatory cytokines and chemokines, such as Tnf-α, Kc, Mcp-1 and Mip2, were upregulated in VDD-fed mice treated with APAP. These results provide experimental data that VDD exacerbates hepatic oxidative stress and inflammation during APAP-induced ALI.

Etiologies and Features of Acute Viral Hepatitis in Spain

BACKGROUND AND AIM

Etiologies of acute viral hepatitis in high-income countries change with migration of populations, lifestyle changes, and emergence of new pathogens. We analyzed etiologies, characteristics, and outcomes of patients with acute viral hepatitis at a tertiary hospital in Spain.

METHODS

We analyzed data from all patients with acute hepatitis (n = 100; 71% male; median age, 42 years; 72% Spanish nationals), older than 16 years, diagnosed in the emergency department of an academic hospital in Barcelona, Spain, from January 2014 through December 2018. Blood samples were collected and patients with serum levels of alanine aminotransferase more than 10-fold the upper limit of normal and markers viral infection were considered to have acute viral hepatitis. We collected clinical information from patients, and samples were analyzed for IgM antibody to hepatitis B (HB) core antigen, HB surface antigen, antibody against hepatitis C virus (HCV), HCV RNA, IgM against hepatitis E virus (HEV), HEV RNA, and IgM against hepatitis A virus (HAV). Patients were followed until resolution of infections or evidence of chronic infection.

RESULTS

The most common etiologies of acute hepatitis were HBV infection (28%), HEV infection (18%), HCV infection (17%), and HAV infection (14%). The main risk factors of the cohort were sexual risk contact and intravenous drug use; 79% of cases of HAV had sexual risk behavior. Twenty-nine percent of patients with acute HAV infection and 29% of patients with HBV infection were immigrants to Spain. Fifty-four patients were hospitalized; jaundice and HCV infection were associated with hospital admission. Three patients died (2 from acute liver failure related to acute HBV infection or HBV and HDV co-infection). Chronic infections developed in 5/28 patients (18%) with acute HBV infection and 7/17 patients (41%) with acute HCV infection.

CONCLUSIONS

Despite universal vaccination against HBV in Spain, HBV remains the most frequent cause of acute viral hepatitis in our emergency department. Almost one-third of cases of acute HBV and HAV infections were immigrants, possibly from countries with suboptimal vaccination programs. A high proportion of patients with acute hepatitis have HEV infection (18%); acute HAV infection was associated with sexual risk behavior.